Re: VDC bitmap with 8x2 cells

From: MagerValp (
Date: 2002-02-01 11:52:01

>>>>> "DW" == David Wood <> writes:

MV> I'm trying to set up the VDC screen to a 640x200 bitmap with 8x2
MV> pixel attribute cells. Char height is set to two, vertical display
MV> registers are quadrupled. I get a screen, but the two rightmost
MV> columns display flickering garbage. Changing the number of
MV> characters per line to 78 or less makes the bug go away. Does
MV> anyone know of a workaround?

DW> This is a silly guess, but have you tried adjusting the dram
DW> refresh? I'm just familiar enough with the VDC to know it has
DW> programmable refresh, and it might need to be changed to suit the
DW> larger amount of data being read.

It does appear to have some sort of effect on the screen bugs, but it
doesn't actually solve the problem. Weird.

    ___          .     .  .         .       . +  .         .      o   
  _|___|_   +   .  +     .     +         .   .  Per Olofsson, konstnär
    o-o    .      .     .   o         +
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